Herbal hepatotoxicity: current status, examples, and challenges.

INTRODUCTION: Herbal medicines have commonly been considered safe by the general public due to their natural origin and long history of traditional uses. In contrast to this belief, many plants produce toxic substances as secondary metabolites that are sometimes not easily distinguishable from the pharmacological active compounds. Some herbal medicines have been associated with adverse effects and toxic effects, including hepatotoxicity, which have been reversed upon discontinuation of the herbal medicine by the patient. AREAS COVERED: This review reflects on selected herbal medicines that are associated with hepatotoxic effects including a description of the phytochemicals that have been linked to liver injury where available. Although case studies are discussed where patients presented with hepatotoxicity due to use of herbal medicines, results from both in vitro and in vivo studies that have been undertaken to confirm liver injury are also included. EXPERT OPINION: Increasing evidence of herbal hepatotoxicity has become available through case reports; however, several factors contribute to challenges associated with causality assessment and pre-emptive testing as well as diagnosis of herb-induced liver injury.